Blowpipe



Nov. 1l, 1947. s. R. oLbHAM BLOWPIPEV Filed Deo. 17, 1942 4R A, m

ATTORNEY Patented Nov. 11, y1947 UNITED STATES PATENT OFFICE BLOWPIPE Samuel R. Oldham, West Orange, N. J., assignor to Union Carbide and Carbon Corporation, a corporation of New York ApplcationDecember 17, 1942; Serial No. 469,286

(Clt 15S-27.4)

14 Claims.

This invention relates to blowpipes, and more particularly to a head and nozzle assembly involving the self-mixing principle.

In blowpipe heads heretofore proposed, the gas chambers are commonly separated by conical seats in a series oi three steps, each step necessarily having its angle properly maintained with relation to its mating angle in the head and having its diameter properly gauged for correct seating. The allowable angle for this type of seat varies approximately from 180 to 30 included angle. The nozzle member having this type of seat is frequently exposed to damage from careless handling. Damaged seats permit crossleakage which results in back-ming, flashbacks, and, in some cases, blowing out of preheat llames when the cutting oxygen valve is opened.

It is therefore the main object of the present invention to avoid seating diiiiculties in the assembly of nozzles and blowpipe heads.

According to the present invention, the gas chambers are separated by cooperating threaded portions of the blowpipe head and nozzle. Also, the nozzle has an inner extension which is provided With cooling ns and projects into one of the gas chambers for the purpose of cooling the nozzle. This extension also serves to protect the threaded portions when the nozzle is removed.

Further objects of the present invention are, therefore, to cool the nozzle and to protect the threads of the nozzle when the same is removed from the blowpipe head.

Other objects and features of novelty will be apparent as the following description proceeds, with reference to the accompanying drawing, in which:

Fig. l is a sectional view through the blowpipe head and nozzle assembly according to the preferred embodiment of the present' invention;

Fig. 2 is a bottom plan view of such assembly;

Fig. 3 is a view in transverse section taken on line 3-3 of Fig. 1;

Fig. 4 is another View in transverse section taken online 4--4 of Fig. 1; and

Fig. 5 is an exploded View of the assembly, showing the blowpipe head in section and the nozzle parts in side elevation.

As shown in the drawing, the novel construction comprises a blowpipe head I0 which is essentially hollow to form a socket or cavity I2, and provided with inlets to receive respectively an oxidizing gas tube I 3, a combustion supporting gas tube I4, and a fuel gas tube I5. The head I0 and its cavity I2 are preferably generally cylindrical, the cavity extending longitudinally of and 2 coaxial With the head I Il. The head IIJ is preferably provided with a triple boss II for the inlets, to receive the tubes or pipes I3, I4, and I5. The gas inlet tubes to the blowpipe head I3 are arranged one above the other, with for example the cutting oxygen tube I3 at the top, the preheat oxygen tube I4 in the middle, and the fuel gas tube I 5 at the bottom. I

Cooperating with the blowpipe head IIJ is a nozzle I6, the gas inlet end oi which is adapted to enter the cavity I 2. The nozzle is provided with an axial passage I I for oxygen, and smaller longitudinally extending passages I8 for the preheat mixture, the passages I8 being symmetrically grouped about the central passage II.

As shown in Fig. 5, the cavity lf2 comprises a central bore, which is internally threaded to form a plurality of spaced threaded bands IS and 20. Between and on each side of the threaded bands are smooth portions comprising the inner end portion 2 I, an intermediate band 22, and the outer end portion 23 of the wall of the cavity I2. The outer end portion 23 terminates in a rim 24. A lateral passage 25 connects the inner end portion 2| with the oxygen tube I3, while a .plurality of passages connect the smooth portions 22 and 23 respectively with the other inlet tubes. In the form shown, paired drillings 21 and 28 extend from the inlet I4 to the intermediate portion 22, and paired drillings 29 and 30 extend from the inlet `I5 to the outer end portion 23.

The nozzle I6, as best shown in Fig. 5, also has externally threaded bands 3I and 32 corresponding to the bands I9 and 20. The nozzle I6 also has an annular groove 33 corresponding to the intermediate portion 22, and an annular groove 34 corresponding to the outer end portion 23. The grooves 33 and 34 are narrowed and deepened by annular cuts at 35 and 36 to intersect the preheating gas mixture passages I8. The nozzle is further provided with a conical seat 3l adapted to engage the rim 24, and its external portion is rendered non-circular as at 38, for example by ilattening or milling, to form a polygonal or squared portion adapted to receive a Wrench.

' The gas inlet end of the nozzle has an extension 39 which is annularly grooved to form cooling ns 4U. In the form shown the extension is a separate member having a head 4I and an externally threaded stem 42. The inner end of the central passage Il is enlarged to form a threaded socket 43, which receives the threaded stem 42, and the head 4I forms a shoulder 44 which overlaps and closes the upper ends of the preheat mixture passages I8. Passing through the head 4| and stem 42 of the extension member 39 is an axial passage 45, shown in Fig, 1 as aligned and communicating with the central passage I1. The gas inlet end of the passage 45 is broached at 46 into hexagonal form to receive an Allen wrench, or slotted t receive a screw driver.

When the nozzle I6 is inserted into the cavity I2 of the head I0 in cooperating relation as shown in Fig. 1, the external threads 3| on the nozzle engage the internal threads I9 in the head I0, and seal off the inner end 2| of the cavity to form a chamber 41, the inner ends of the preheat mixture passages I8 being closed and sealed by the overlapping shoulder 44 of the extension member 39. The cutting oxygen from the tube I3 passes through the passage 25 into the cha-mber 41, around and over the extension member 39 with its cooling ns 40. The extension member 39 and the cooling fins 40 project into the chamber 41 in the path of the incoming stream of oxygen, which cools the nozzle I6. The stream of oxygen then passes into the broached end 46 and through the passage 45, and thus on out through the central passage I1.

At the same time, the external threads 32 on the nozzle engage the internal threads 20 in the head I0 and seal an annular chamber 48 formed by the groove 33 in the nozzle and the intermediate smooth portion 22 of the blowpipe head cavity wall. The preheat oxygen from the tube I4 o'ws through the paired drillings 21 and 28 into the chamber 48, and is distributed therearound to the intersections of the cut 35 with the preheat mixture passages I8, through which the preheat oxygen flows outwardly or down along the nozzle.

At the same time, the conical seat 31 on the nozzle engages the rim 24 on the blowpipe head and seals an annular chamber 49, which is formed by the groove 34 in the nozzle and the smooth end portion 23 of the blowpipe head cavity I2. Fuel gas, such as acetylene from the tube I5, passes through the paired drillings 29 and 30 into the chamber 49 and is distributed therearound to the cut 36 and the intersections thereof with the passages I8 where it mixes with the preheat oxygen in the same passages coming from the chamber 48. The mixture thus formed is discharged from the outlet ends of the passages I8 to form the preheat flames.

It should be noted that the preheating gases are distributed to the passages I8 in the nozzle I6 by the annular chambers 48 and 49, which are respectively formed for example by removing sections of the screw thread from both the nozzle IB and the blowpipe head I0. The preheating gases enter the annular chambers 48 and 49 through the paired drillings 21 and 28, and 29 and 30, from the gas inlet tubes I4 and I 5. These paired drillings provide substantially even distribution of gas about the chambers 48 and 49, and reduce overfeeding of the preheat flames on the gas inlet side of the chambers. This even distribution of the gases in the inlet chambers 48 and 49 applies to both gases, the preheat oxygen and the fuel gas, the overfeeding of either of which would result in uneven length and unbalanced mixtures in the preheating flamesl The one seat 31 on the nozzle I6 is located between the external portion 38 and the acetylene inlet chamber 49. This seat is provided to prevent leakage oi acetylene to the atmosphere and it mates with a seat formed by the rim 24 recessed into the face of the blowpipe head III. The cutting oxygen passage I1 has a reduced diameter section 50 which is for the purpose of pro- 4 viding higher velocity at the nozzle, more even gas flow, and controlled gas expansion.

When overhaul, adjustment, or replacement is desired, the nozzle I6 may be removed by a suitable wrench applied to the portion 38. The extension member 39 protects the exposed threads of the removed nozzle from damage due to careless handling.

An endwise blow which would otherwise burr the inner end of the threaded portion 3|, is received by the head 4I. If the nozzle were dropped on a cement floor, for example, the impact is received by the head 4I and the external portion 38 so that the threaded portions 3| and 32 bridge over and are spaced upward from the floor, and thus protected from sidewise ilattening.

By means o-f a Wrench inserted in the broached end 46, the threaded stem 42 can be unscrewed from the socket 43 to remove the member 39 and thus expose the upper ends of the preheat passages |8 to facilitate cleaning thereof.

In practically all previous designs of both cutting and welding pipes, when nozzles are threaded into the blowpipe head, seizing or gallingof the threads takes place due mainly to a poor bearing condition between nozzle and head or the presence of foreign matter lodged in the threads. Damaged male threads also account for considerable difficulty. In many cases the nozzle is twisted 01T, leaving the threaded portion lodged in the blowpipe head. This not only renders the apparatus inoperative, but it also necessitates an expensive repair involving removal and replacement of the blowpipe head in many cases. In the present embodiment such diiliculties have been practically eliminated through the use of a hard bronze with good bearing properties. This alloy, designated as Oxweld No. 17 composition, consists of copper 83%; zinc 10%; silicon 5%; aluminum 1% and manganese 1%. This material does not seize in contact with copper under any conditions tested including temperatures of the order of 900 F.

From the foregoing description it will be readily apparent that the present invention provides a better bearing and non-binding condition between the nozzle and the head, elimination of conical seats by provision of multiple threads, a nned extension projecting into the cutting oxygen inlet chamber which acts as a heat dissipator and thread protector, the same being readily removable if it becomes necessary to clean passages, and paired inlet holes providing for the admittance of the preheatng gases to the distribution chambers in the head. More nearly equal pressure and less tendency towards overieeding preheating llames on the inlet side of the head are thus obtained.

I-Iaving thus described the invention, I claim:

l. A blowpipe head having a cavity and spaced inlets rior combustion supporting and fuel gases, and a relatively short and thick nozzle extending within and cooperating with said cavity and having a longitudinal passage for combustion supporting gas and other longitudinal passages for preheat gas, said cavity and nozzle having annular chambers respectively communicating with said inlets, said cavity and nozzle having threaded portions interposed between said chambers for securing said nozzle in said cavity in cooperating relation, the innermost of said chambers being larger than the internal diameter of said threaded portions and connected to said inlet for combustion supporting gas, said innermost chamber being positioned ahead of said threaded portions and being larger than said inlet, the inner end of said nozzle having an extension beyond said threaded portions extending into said chamber but out of contact with the wall of said cavity and following substantially the contour thereof to provide substantial gas contact therewith by combustion supporting gas from said inlet which passes over and around said extension in said innermost chamber and out through the combustion supporting passage in said nozzle to form a cutting jet.

2. A blowpipe head having a cavity and spaced inlets for cutting oxygen, preheat oxygen, and fuel gas respectively, and a nozzle extending within and cooperating with said cavity, said cavity and nozzle having annular chambers respectively communicating with said inlets, said nozzle having an axial passage for cutting oxygen, and other longitudinally extending passages for preheat mixture, said preheat mixture passages intersecting both said preheat oxygen chamber and said fuel gas chamber, and detachable means at the inner end of said nozzle and entering the innermost of said chambers for sealing the inner ends of said preheat mixture passages from the path of the cutting oxygen.

3. A blowpipe nozzle having an axial passage and other longitudinally extending passages grouped about said axial passage, and detachable means at the inner end of said nozzle for sealing the inner ends of said grouped passages.

4. A blowpipe nozzle having an axial passage, and other longitudinally extending passages grouped around said axial passage, in combination with an extension member for said nozzle, said axial nozzle passage having a portion of increased diameter at its gas inlet end and provided with internal threads, said extension member having a stem provided with `external threads engaging said internal threads and a shoulder overlapping and sealing said grouped passages.

5. A blowpipe head having a cavity and spaced inlets for combustion supporting and fuel gases, and a nozzle extending Within and cooperating with said cavity, said cavity and nozzle having gas chambers respectively communicating with inlets whereby one of said chambers receives combustion supporting gas and another of said chambers receives fuel gas, said nozzle having an axial passage for combustion supporting gas and other longitudinally extending passages for preheat mixture, said combustion supporting gas passage of said nozzle having an enlarged and threaded inner end, in combination with a member having a head in said combustion supporting gas chamber, a shoulder sealing the ends of said preheat mixture passages, and a stem in said threaded end, said member having a central passage aligned with said combustion supporting gas passage.

6. A blowpipe head having a cavity and spaced inlets for combustion supporting and fuel gases, and a nozzle extending within and cooperating with said cavity, said cavity and nozzle having gas chambers respectively communicating with said inlets, said nozzle having an axial passage for combustion supporting gas and other longitudinally extending passages for preheat mixture, said combustion supporting gas passage having an enlarged and threaded end forming a socket, in combination with a member having a head in said combustion supporting gas chamber and a threaded stem in said socket, the underside of said head forming a shoulder sealing the 6 end of said preheat mixture passages, said member having a cylindrical passage aligned with said combustion supporting gas passage whereby combustion supporting gas from said inlet passes over said head in said combustion supporting gas chamber through said cylindrical passage and out of said axial passage to form a cutting jet, said head being rotatable within said combustion supporting gas chamber to prevent unscrewing of said stem when said nozzle is removed.

'7.` A blowpipe head having a cavity and spaced inlets for combustion supporting and fuel gases, and a nozzle extending within and cooperating with said cavity and having an axial combustion supporting gas passage with an outlet adapted to project a cutting jet, said cavity and nozzle having gas chambers. respectively communicating with said inlets, the innermost of said chambers communicating with the combustion supporting gas inlet, the inner end of the nozzle being provided with an extension having cooling iins extending into said whereby combustion supporting gas from said inlet passes over and around said cooling fins in said innermost chamber and out through said axial nozzle passage to form said cutting jet.

8. A blowpipe nozzle having an axial cutting oxygen passage and longitudinally extending preheat mixture passages grouped around said cutting oxygen passage, said nozzle having passages for introducing fuel and combustion supporting gas to said pre-heat mixture passages intermediate their ends, and a detachable end member for said nozzle having a central passage registering with said cutting oxygen passageand an annular shoulder overlapping and closing the ends of said pre-heat passages, whereby said end member may be removed and cleaning wires pushed entirely through said pre-heat passages.

9. A blowpipe head having a cavity and spaced inlets for combustion supporting and fuel gases, said cavity comprising recesses and threaded portions, the internal diameter of said threaded portions being more restricted than said recesses, said head having passages leading from said inlets and intersecting said cavity recesses, and a nozzle having an axial combustion supporting gas passage with an outlet adapted to project a cutting jet and an externally threaded inlet end adapted to be screwed into said spaced threaded portions, the inner end of the nozzle having cooling ns extending into the innermost of said recesses, whereby combustion supporting gas from said inlet passes over and around said cooling ins in said innermost recess and out through said axial passage to form said cutting jet; said cooling fins being of a smaller diameter than the restricted internal diameter of said threaded portions, whereby said ns may be removed with said nozzle.

10. A blowpipe head having a cavity and an inlet thereto for combustion supporting gas, and a nozzle entering said cavity, said nozzle and the wall of said cavity having contacting portions sealing 01T the inner end of said cavity to form a chamber receiving combustion supporting gas from said inlet, said nozzle having a longitudinal combustion supporting gas passage with an outlet end adapted to project a cutting jet, the inner end of said nozzle having cooling fins spaced around said passage and extending into said chamber, whereby combustion supporting gas from said inlet passes over and around said cooling ns in said chamber te cool said nozzle innermost chamber and on through said passage to form said cutting jet.

1,1. A blowpipe head and nozzle as claimed in claim 10, in which said contacting portions are screw threads, the inner end of said cavity is larger than the internal diameter` of said threads, and said cooling ns are of a diameter smaller than the internal diameter of the threads, Whereby said ns may be removed with said nozzle.

12. A blowpipe nozzle as claimed in claim 8, and a blowpipe head having a cavity and an inlet thereto for combustion supporting gas, said nozzle and the Wall of said cavity having screw threads sealing 01T the inner end of said cavity to form a chamber receiving combustion supporting gas from said inlet, said detachable end member having a head forming said shoulder and rotatable in said cavity beyond said screw threads, whereby said member turns with said nozzle when the nozzle is unscrewed.

13. A blowpipe nozzle having an axial passage and other longitudinally extending passages grouped about said axialpassage, said nozzle having a passage for introducing fuel gas to said grouped passages intermediate their ends, and detachable means at the inner end of said nozzle for sealing the inner ends of said grouped passages.

14. A blowpipe head having a cavity and an inlet thereto Ifor combustion supporting gas, and a nozzle entering said cavity, said nozzle and the wall of said cavity having contacting portions sealing oii the inner end of said cavity to form a chamber receiving combustion supporting gas from said inlet, said chamber being larger than said contacting portions, said nozzle having a relatively short straight longitudinal passage for combustion supporting gas and having an outlet end relatively close to its inlet end for projecting REFERENCES CITED The following references are of record in the le of this patent:

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